Condenser tube plug



1 65 J. M. HINDMAN 3,203,479

CONDENSER TUBE PLUG Filed June 4, 1963 42v; W 1 /25 ff l .5'0 F76. 4 Z %77 INVENT R JOE M. x/m/o/w/v 1 70. 6

United States Patent 3,203,479 CONDENSER TUBE PLUG Joe M. Hindrnan, Kenedy, Tex., assignor to Warren Petroleum Corporation, Tulsa, Okla., a corporation of Delaware Filed June 4, 1963, Ser. No. 285,527

3 Claims. (Cl. 165-134) This invention relates to a tube plugging device for use with shell and tube heat exchangers where it is desired to plug a leaking tube without dismantling the entire apparatus.

One method of plugging leaking tubes in a shell and tube heat exchanger is to first locate the leaking tubes and then dismantle the exchanger so as to expose both ends of the tubular bundle. Plugs are then driven into both ends of the leaking tubes. The floating and stationary head covers and the shell cover are then replaced.

Devices have previously been proposed to plug leaking tubes in a shell and tube heat exchanger without removing the shell cover or floating head, but these devices suffer from the disadvantages of being complex in structure and thereby difficult to fabricate. The device of the present invention is simple in design, easy to fabricate out of readily available materials, and is useful for plugging leaking tubes in conventional shell and tube heat exchangers with a minimum of time and eifort.

The device of this invention is adapted to be used in plugging a tube in a tubular bundle in a shell and tube heat exchanger while the tubular bundle remains in the shell. The device comprises a sleeve member which has an outside diameter substantially the same as the inside diameter of the tube and which is adapted to fit inside the tube, and a tapered plug'member also adapted to fit inside the tube. The sleeve member is adapted to abut the internal surface of the end cover of the shell and extend into the tube end to be plugged a distance suflicient to effectuate a seal of the tube when the sleeve member is forcibly expanded against the internal surface of the tube. The smaller end of the plug member is adapted to pass into the sleeve member while the larger end of the plug member is adapted to expand the end of the sleeve member and effectuate a seal with the internal surface of the tube to be plugged when the plug member is forcibly inserted into the sleeve member whilethe sleeve member abuts the shell. In one embodiment of this invention the end of the sleeve member which abuts the shell is sealed.

The invention will be further described with reference to the attached drawings of which FIGURE 1 is a longitudinal cross section of a floating head type shell and tube heat exchanger.

FIGURE 2 is an enlarged cross section of one of the tubes of the shell and tube heat exchanger with the device of the subject invention in place.

FIGURE 3 represents the device of the subject invention with a portion of the sleeve member broken away.

FIGURE 4 represents a driving rod means with a portion broken away to be used with the device of this in- Vention.

FIGURE 5 shows another embodiment of the sleeve member of the subject invention.

FIGURE 6 shows yet another embodiment of the sleeve member of the subject invention.

Referring to FIGURES 1 and 2, numeral 10 defines the shell of a floating head type of shell and tube heat exchanger. Numeral 12 designates the tubular bundle (only one tube shown) comprising individual tubes 14 held in place by a plurality of tube support sheets 16. Numeral 18 defines the stationary tube support sheet at one end of the tubular bundle 12 while a floating tube sheet 20 supports the tubes at the other end. Numeral 21 defines one end cover for the shell. A floating head cover 22 is removably attached to the floating tube sheet 20 by any suitable means such as by threaded bolts and nuts (not shown). A stationary channel cover 24 is ,removably attached to the stationary tube support sheet 18 and shell 10 by any suitable means such as threaded bolts and nuts (not shown). The stationary channel cover 24 is provided with an inlet 26, an outlet 28, a stationary head cover 29, and a separation bafile 30. The shell 10 is likewise provided with an inlet 32 and an outlet 34. Spacers and tie rods 35 can also suitably be provided.

Refering more specifically to FIGURES 2 and 3, numeral 36 defines a sleeve member which is a hollow substantially cylindrical member. Numeral 38 designates a tapered plug member adapted to expand the sleeve member 36 when the plug 38 is forcibly inserted into the sleeve member 36. I

Referring specifically to FIGURE 2, the sleeve member 36 and plug member 38 are in place and functioning to seal the leaky tube 14. The length of the sleeve member 36 is such that it abuts the floating head 22 and extends into the tube 14 a suflicient distance to effectuate a seal of the tube when expanded by the forced entry of the tapered plug member 38.

The method of plugging a leaky tube with a device of the subject invention is easily seen from the drawings. The stationary channel cover 24 is removed and after the faulty tube or tubes have been located by any suitable testing method and cleaned, if desired, the length of the sleeve member 36 is determined by any suitable procedure. For example, one procedure would be to insert a driving rod 40 (see FIGURE 4) into the faulty tube 14 until it touches the inside of the floating head 22 of the exchanger. The rod 40 could then be marked, removed and the exchanger tube length subtracted to determine the distance from the end of the tube to the floating head cover 22. The length of the sleeve member 36 would then be this distance from the end of the tube to the floating head cover plus an additional length suflicient to effectuate a seal with the internal surface of the tube to be plugged when the external surface of the sleeve member is forcibly expanded against the internal surface of the tube while the sleeve abuts the shell. The sleeve member is usually at least 0.5 inch and preferably between 0.5 and 5 inches longer than the distance between the tube end to be plugged and the end cover of the shell or floating head cover if a floating head type of shell and tube heat exchanger is employed.

The sleeve member 36 of proper length is inserted into the leaky tube from the stationary tube support sheet 18 end. The sleeve is pushed through the tube 14 by any suitable means, such as, for example, by means of the drive rod 40 shown in FIGURE 4. The tapered plug member 38 is then inserted as shown in FIGURE 2, that is, the smaller end enters the tube 14 first. The plug member 38 is also pushed through the tube 14 by any suitable means, such as the drive rod 40. The smaller end of plug member 38 has a further taper to permit easy entry of the plug member 38 into the sleeve member 36. The sleeve member 36 will abut against the floaing head cover 22 which then serves the purpose of providing a holding support for the sleeve member 36 while the plug member 38 is driven into the sleeve member 36 until the desired expansion is obtained. The plug member 38 is driven by any suitable means, such as, for example, by placing the cylindrical portion 42 of the driving means 40 against the end of the plug member 38 and applying a force to the head 44 of drive rod 40. Referring to FIGURE 2, it is obvious that plug member 38 is urged through compressive force into sleeve member 36 which is urged into sealing engagement with the tube 14 substantially at the tube support sheet 20 through compressive force.

FIGURE 4 refers specifically to a drive rod 40 which comprises a substantially cylindrical member 42. The outside diameter of the cylindrical member 42 is substantially the same as the outside diameter of the sleeve member 36 so as to allow the drive rod 40 to push the sleeve member through the leaking tube. The length of a cylindrical member 42 is sufficient to extend through the tube 14 and abut the floating head cover 22. If desired, the one end 44 or drive rod 40 can be enlarged to prohibit the entry of the head 44 into the tube 14.

As shown in FIGURE 3, the diameter (D of the larger end of the tapered plug is slightly less than the inside diameter (D of the tube to be plugged. In similar manner, the outside diameter (D of the sleeve member 36, is slightly less than the inside diameter (D of the tube. The diameter (D of the smaller end of the tapered plug is less than the inside diameter (D of the sleeve member so as to be able to be inserted into the sleeve member. In order for the device of this invention to function properly, that is, in order to have the device of this invention effectuate a seal of the leaking tube, the plug member 38 must be adapted to expand the sleeve member 36. One means of achieving this is to have the diameter (D of the larger end of the plug member 38 greater than the inside diameter (D of the sleeve member. In addition, the numerical difference between the inside diameter (D of the tube and the outside diameter (D of the sleeve member 36 must be less than the difference between the diameter (D of the larger end of the plug member 38 and the inside diameter (D of the sleeve member 36, that is, D D must be greater than D D It is preferred that (D D be very small, usually 0.010 and 0.015 inch. It is also preferred that the wall thickness of the sleeve member 36 (B -D be between 0.05 and 0.3 inch, and more preferably be between 0.08 and 0.15 inch. It is additionally preferred that between and percent of the length of the plug member freely enter the sleeve member without binding. It is additionally preferred that that the diameter of the plug member (which continuously increases from the smaller to the larger end) be equal to the inside diameter of the sleeve (D at some point between 20 and 60 percent of the total length of plug member from the smaller end. The plug member can be any suitable length and is usually at least 3 inches long, and preferably between 3.5 and 4.5 inches in length.

FIGURE 5 shows another embodiment for the sleeve member of this invention. In FIGURE 5, numeral 46 refers to the sleeve member. One end of the sleeve member 46 is opened to receive the tapered plug 38, while the other end is sealed by any suitable means, such as a bottom plate 48. A sleeve member 46, such as that shown in FIGURE 5, would be particularly advantageous to use in shell and tube heat exchangers where the pressure of the medium circulating inside the tube exceeds the pressure of the fluid in which the heat exchange tube is immersed.

In this case, the differential pressure would tend to dislodge the plug it the sleeve were opened on the end which abuts the inside surface of the shell or floating head cover. By sealing the end of the sleeve member which abuts the inside surface of the shell or floating head cover, this differential pressure effect is eliminated. On the other hand, when the pressure of the medium in which the heat exchange tube is immersed exceeds the pressure of the fluid circulating within the tubes, the tapered plug member has a differential pressure tending to urge the plug member into sealing engagement with the tube, and then there is little advantage to having the opposite end of the sleeve member sealed.

Referring to FIGURE 6, numeral 50 refers to yet another sleeve member embodiment. The inside wall of the sleeve member 50 is tapered to complement the taper of the initial 20 to percent of the length of the plug member starting at the smaller end. In this manner, the sleeve member 50 will expand more uniformly over a longer distance and form a seal along a greater length of the tube. Even with a tapered sleeve member 50, it is preferred that only between 20 and 60 percent of the length of the plug member enter the sleeve member before the diameter of the plug member is equal to the initial inside diameter of the sleeve member 50. When the diameter of the plug member 38 is equal to the initial inside diameter of the sleeve member, force is necessary for continued entry of the plug member which results in expansion of the sleeve member against the inside surface of the tube to be sealed.

The material from which the sleeve and plug members of the device of this invention is made is not critical, bot should be such as to withstand corrosion due to the medium in which the materials are to be employed. It is preferred that the material for both the sleeve and plug members be metallic, but other materials, such as the various plastics, can suitably be employed. Since the sleeve member must expand upon entry of the plug member, the sleeve member must be made of a softer material than the plug member. Anyone skilled in the art can easily determine if any particular materials are suitable by fabrication of a sleeve and plug member, followed by forcible entry of the plug member into the properly contained sleeve member to determine if expansion is achieved. For example, bronze is a suitable material for the sleeve member, if steel is employed for the tapered plug member.

One of the advantages of the device of the subject invention is its simplicity of design. This simplicity was made possible by the use of a portion (the floating head or shell) of the shell and tube heat exchanger itself to aid in the plugging of the leaky tubes. That is, the length of the sleeve or cylindrical member of the subject invention must be longer than the distance between the end of the tubes and the floating head or shell so that the farther end of the sleeve member abuts the floating head and is held in place while the tapered plug member is driven into and expands the nearer end of the sleeve member to effectuate a seal.

Resort may be had to such variations and modifications as fall within the spirit of the invention and the scope of the appended claims.

I claim:

1. An apparatus comprising:

a tubular bundle comprising a plurality of individual tubes;

a shell surrounding said tubular bundle;

means to support said tubular bundle within said shell;

a head cover removably attached to one end of said shell;

a sleeve member having an outside diameter substantially the same as the inside diameter of one of the tubes of the tubular bundle and adapted to fit inside said tube, said sleeve member being longer than the distance between the tube end to be plugged and said shell cover, said sleeve member abutting said head cover and being in sealing engagement through compressive force with said tube; said sleeve member transmitting a portion of the compressive force to said end cover; and

a tapered plug member in sealing engagement through compressive force with said sleeve, the smaller end of said plug member being within said sleeve while the larger end of said plug member extends beyond the sleeve into the tube to be plugged.

2. An apparatus comprising:

a tubular bundle comprising a plurality of individual tubes;

a tube support sheet at the end of said tubular bundle;

a shell surrounding said tubular bundle;

means to support said tubular bundle within said shell;

head cover removably attached to one end of said shell;

sleeve member having an outside diameter substantially the same as the inside diameter of one of the tubes of the tubular bundle and adapted to fit inside said tube, said sleeve member being longer than the distance between the tube end to be plugged and said shell cover, said sleeve member abutting said head cover and being in sealing engagement through compressive force with said tube substantially at the tube support sheet, said tube support sheet absorbing at least a portion of said compressive force, and said sleeve member transmitting a portion of the compressive force to said end cover; and

a tapered plug member in sealing engagement through compressive force with said sleeve, the smaller end COVGI'.

References Cited by the Examiner UNITED STATES PATENTS Kofoed et a1. '29523 Feldhoif 285382.4 Voreck 165--95 Hoerter 122--364 Franck 138-89 Knecht 13889 CHARLES SUKALO, Primary Examiner. 

1. AN APPARATUS COMPRISING; A TUBULAR BUNDLE COMPRISING A PLURALITY OF INDIVIDUAL TUBES; A SHELL SURROUNDING SAID TUBULAR BUNDLE; MEANS TO SUPPORT SAID TUBULAR BUNDLE WITHIN SAID SHELL; A HEAD COVER REMOVABLY ATTACHED TO ONE END OF SAID SHELL; A SLEEVE MEMBER HAVING AN OUTSIDE DIAMETER SUBSTANTIALLY THE SAME AS THE INSIDE DIAMETER OF ONE OF THE TUBES OF THE TUBULAR BUNDLE AND ADAPTED TO FIT INSIDE SAID TUBE, SAID SLEEVE MEMBER BEING LONGER THAN THE DISTANCE BETWEEN THE TUBE END TO BE PLUGGED AND SAID SHELL COVER, SAID SLEEVE MEMBER ABUTTING SAID HEAD COVER AND BEING IN SEALING ENGAGEMENT THROUGH COMPRESSIVE FORCE WITH SAID TUBE; SAID SLEEVE MEMBER TRANSMITTING A PORTION OF THE COMPRESSIVE FORCE TO SAID END COVER; AND A TAPERED PLUG MEMBER IN SEALING ENGAGEMENT THROUGH COMPRESSIVE FORCE WITH SAID SLEEVE, THE SMALLER END OF SAID PLUG MEMBER BEING WITHIN SAID SLEEVE WHILE THE LARGER END OF SAID PLUG MEMBER EXTENDS BEYOND THE SLEEVE INTO THE TUBE TO BE PLUGED. 